As we continue to grind through our Top 30 Mariners prospects list, we have finally reached the Top 15. Today’s list is almost exclusively made of players who have joined the organization in the past calendar year.
Of course, this is a good thing. The Mariners needed drastic additions to their farm system to set themselves up for the future. In fact, 11 of the top 15 on our list joined the organization in that time period.
As we continue our rundown, keep in mind that you can get a breakdown of our thought process by reading the primer. For a look at who we ranked 16-20, you can click here. Remember the scouting grades are on a 20-80 scale and the probability grade is based on the likelihood they reach 75% of their ceiling. Now let’s get started.
Casetta-Stubbs first crossed my radar when the Mariners drafted him in the 11th round of the 2018 draft. He pitched at Kings Way Christian School in Vancouver, Washington and was the first high school player they selected.
The Mariners then proceeded to hand the 18-year-old a $325,000 signing bonus. This bonus is typically given out to a 5th round pick, so seeing the bonus amount certainly puts Casetta-Stubbs on our radar.
Stuff-wise, Casetta-Stubbs has a fastball with good movement that sits 91-95 mph and has been clocked as high as 97 per reports. The slider appears to be his best chance at a plus off-speed pitch with its sharp break.
Casetta-Stubbs changeup and command still need work but at 18-years-old, he has plenty of time to figure both out. He is a good athlete who also earns high marks for his makeup and feels for pitching, giving him a higher floor than most high school arms.
As for his first year as a pro, Casetta-Stubbs probably stays in Peoria for extended Spring Training and may get a few innings for Everett if everything goes right. The one comp I have heard that seems to make sense is former Mariners prospect and Boston Red Sox folk hero Derek Lowe.
With a bit of patience, Casetta-Stubbs can #3 starter upside. If the third pitch never comes, he has a high ceiling of a middle reliever with his fastball/slider combination.